Which was the last human chromosome to be completely sequenced ?

Options

A. Chromosome 1
B. Chromosome 11
C. Chromosome 21
D. Chromosome x

Answer

To solve the question "Which was the last human chromosome to be completely sequenced?", we can follow these steps:

### Step 1: Understand the Question
The question asks for the last human chromosome that was completely sequenced. We need to identify which of the given options is correct.

### Step 2: Review the Options
The options provided are:
1. Chromosome 1
2. Chromosome 11
3. Chromosome 21
4. Chromosome X

### Step 3: Analyze Each Option
- **Chromosome 1**: This is one of the largest human chromosomes and was indeed one of the last to be sequenced. It was completed in May 2006.

- **Chromosome 11**: This chromosome is not the last to be sequenced. It has 135 million base pairs and was sequenced earlier than chromosome 1.

- **Chromosome 21**: This is the smallest human autosome and is associated with Down syndrome. It is not the last chromosome to be sequenced.

- **Chromosome X**: This is a sex chromosome present in both males and females, consisting of 53 million base pairs. It was sequenced before chromosome 1.

### Step 4: Conclusion
After analyzing all the options, we find that **Chromosome 1** is the last human chromosome to be completely sequenced.

### Final Answer
The last human chromosome to be completely sequenced is **Chromosome 1**.

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